Proxy pattern

class Place
  def rent
    puts "oh, don't call me"
  end
end

class House < Place
  def rent
    puts "make rent"
  end
end

class HouseAgency < Place
  attr :real_place

  def rent
    puts "rise 100% in price"
    @real_place ||= House.new
    @real_place.rent
  end
end

# console
house_agency = HouseAgency.new
house_agency.rent